A wireless identification marker is understood to mean any wireless entity comprising a component with reduced dimensions, comprising a circuit and transmission/reception means. The marker may, for example, be a Radio Frequency Identification (RFID) label, the transmission/reception means of which comprise a radio antenna. It may also involve a contactless smart card. An infrared marker may also be envisaged.
Wireless markers of this type are known and are capable of transmitting, at the request of a wireless identification reader, a unique identifier comprising around one hundred bits over a distance of several meters.
Some of these markers, such as the RFID labels, for example, have low computing capacities. This rules out the possibility of securing the transmissions with a corresponding reader using conventional arithmetically based solutions.
However, use of these markers can only be conceived and generalized if it provides for sufficiently reliable security mechanisms.
To this end, it has been proposed to exploit the noise inherent in the communication channel between a marker and a corresponding reader to provide confidentiality of exchanges in the presence of a passive attacker, i.e. an attacker content to listen to exchanges without interacting with the marker or reader.
However, even if the protocol proposed for this purpose has the merit of being simple to implement, it is based on the hypothesis that the errors with which the attacker is confronted when listening to the exchanges are independent from those introduced by the noisy communication channel between the marker and the reader.
In practice, this hypothesis is not always verified. In particular, the attacker may have sufficient listening capacities to determine the data received by the marker or the reader through correlation on the basis of the data which he receives.
An object of the present invention is to offer a more satisfactory level of security between a wireless identification reader and a wireless identification marker.